Refrigerated trailers have made the transition to new Thermo King and Carrier reefer units that emit fewer exhaust emissions demanded by EPA, and are ever-more capable of monitoring and keeping loads at exactly the right temperatures.

S., told HDT when we visited his booth at the Mid-America Trucking Show in March.

“‘What’s the difference in weight and cost for different materials?

Meanwhile, refrigerated trailer builders continue to improve the thermal performance of walls, ceilings and floors, and address demands for durability and longevity.

Doonan Specialized – At MATS, featured an RGN hydraulic-gooseneck lowboy with an 18-inch deck height, a Honda 13-hp pony motor and a 35-ton rating with three axles; a folding-gooseneck, four-axle lowboy with four main beams, 40- to 42-inch deck height and 60-ton rating; and a 48-foot by 102-inch-wide aluminum flat on a spread tandem with a 7,800-pound tare weight rated at 50,000 pounds in 4 feet.

’”He had graphic answers right there: three spread-tandem, drop-deck trailers he dubbed “good, better and best.” Here’s how they stacked up, literally: On top was the good one, a steel trailer, the least costly at about $28,000 but heaviest at 11,700 pounds.